The circulatory system consists of the heart, blood vessels, and blood. The heart pumps blood through two circuits - the pulmonary circulation which carries blood to the lungs to receive oxygen and release carbon dioxide, and the systemic circulation which carries oxygenated blood to the rest of the body. Blood travels through arteries, capillaries, and veins, carrying oxygen, nutrients, hormones, and waste products like carbon dioxide. Maintaining a healthy diet, avoiding smoking and junk food, exercising regularly, and keeping a healthy weight can help support a good circulatory system.